Implementation of the Incomplete Gamma function committed



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Implementation of the Incomplete Gamma function

New Maxima User function: gamma_incomplete(a,z)

The following features are implemented:

1. Evaluation for real and complex numbers in double float and bigfloat
precision
2. Special values for gamma_incomplete(a,0) and gamma_incomplete(a,inf)
3. When $gamma_expand T expand the following expressions:
     gamma_incomplete(0,z)
     gamma_incomplete(n+1/2)
     gamma_incomplete(1/2-n)
     gamma_incomplete(n,z)
     gamma_incomplete(-n,z)
     gamma_incomplete(a+n,z)
     gamma_incomplete(a-n,z)
4. Mirror symmetry (commutes-with-conjugate T)
5. Derivative wrt the arguments a and z

Modified files:

gamma.lisp
rtest_gamma.mac
testsuite.lisp

Tested with GCL 2.6.8 and CLISP 2.44.